<template>
  <div class="son">
    我是son
    <button @click="fn">修改sonName</button>
    <p>{{ sonName }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      timerId: null,
      sonName: '子1'
    }
  },
  methods: {
    fn () {
      this.sonName = '子子孙孙'
    }
  }
}
</script>

<style>
.son {
  width: 300px;
  height: 300px;
  border: 1px solid #000;
}
</style>